FindQt4: Set the INTERFACE_QT_MAJOR_VERSION for Qt4::QtCore

With a similar commit in Qt 5, this will error at CMake time if
an attempt is made to use

 target_link_libraries(foo Qt4::QtCore Qt5::Core)

1 files changed, 8 insertions, 0 deletions

diff --git a/Tests/RunCMake/IncompatibleQt/main.cpp b/Tests/RunCMake/IncompatibleQt/main.cpp
new file mode 100644
index 0000000..140a7c1
--- /dev/null
+++ b/Tests/RunCMake/IncompatibleQt/main.cpp
@@ -0,0 +1,8 @@
+
+#include <QCoreApplication>
+
+int main(int argc, char **argv)
+{
+  QCoreApplication app(argc, argv);
+  return app.exec();
+}